Field of Invention
Various embodiments of the present invention relate to a distributed file system capable of providing a snapshot of a file level, and more particularly, to a distributed file system configured to manage file data distributed and stored in chunk units with read-only snapshot files or writable snapshot files.
Description of Related Art
A distributed file system is a system configured to store and manage meta data and actual data of a file, separately. In general, meta data is a data that explains another data, and thus is also called attribute data. Meta data is managed in a meta data server, while actual data is distributed and stored in a plurality of data servers. Meta data includes information on the data servers where the actual data is stored.
The meta data server and plurality of data servers have a distributed structure where the servers are connected via a network. Therefore, a client has different paths for approaching the meta data and the actual data of a file. That is, in order to approach a file, the client first has to approach the meta data of the file stored in the meta data server and obtain information on the plurality of data servers where the actual data is stored. Then, inputting and outputting of the actual data is performed through the plurality of data servers.
A snapshot is generally used to support backing up operations at online situations by storing a current state of a file of a certain point at the file system or volume level. Recently, snapshots have been used to enable returning to a snapshot state of a certain time point as a virtual desktop image or a snapshot of a virtual disc is provided in a virtual desktop environment. Snapshots of virtual desktop images have also been used to distribute the virtual desktop images quickly.
In such a case, file-level snapshots capable of mapping and managing virtual desk top images or virtual disks at the file level must be provided in the file-based distributed file system.